Hair dryer

ABSTRACT

A hair dryer provides a multi-stage air current feed device to accelerate the flow velocity of the air current in the hair dryer such that the motor and the fans may generate least noise while the hair dryer is in operation. In addition to multiple stages of the air current feed device, a further added acceleration can be performed by way of applying the Bernoulli&#39;s law and the Venturi. Furthermore, a conventional hair dryer also can reduce the noise thereof without lower down the original high flow velocity and the flow rate thereof by way of applying the Bernoulli&#39;s law and the Venturi.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a hair dryer, and, particularly, to an improved hair dryer, which provides a plurality of fan blade assemblies to accelerate the air current therein and provides additional acceleration parts attached to the casing thereof so as to offer a strong output of air current as well as a low sound generation.

[0003] 2. Description of Related Art

[0004] Usually, the conventional hair dryer provides a motor associated with a blade wheel, and in order to maintain a powerful output of air current, the motor has a rotational speed around 1,000 revolutions per minute. Unfortunately, the sound lever produced by the conventional hair dryer is always higher than 60 decibels so that the user is often bothered by the noise from the conventional hair dryer. Mostly, the conventional hair dryer can be classified into two categories, the centrifugal type and the axial flow type.

[0005] Referring to FIG. 1, a centrifugal type hair dryer provides a blade wheel 11 joined to the motor in the casing 10 and the motor turns with a high rotational speed to drive the blade wheel 11 so that the air current can be sent out from the casing 10 with a high velocity and a high flow rate.

[0006] Referring to FIG. 2, an axial flow type hair dryer provides a conical blade wheel 13 in the casing joined to a motor 12 and the blade wheel 13 is attached with blades 14. The outer rim of each of the blades 14 has the same taper as the blade wheel 13, and the blades 14 are covered with a conical shield 15, which provides a bowl space at the inner side thereof so as to be passed through by the air current. The motor 12 at the other side thereof has turbulent wings 16 next to the casing to correspond to both of the blade wheel 13 and the conical shield 15 so that the random air current may not generate at the central area in the casing to avoid the noise and the vibration as soon as the air is sucked into the casing.

[0007] A U.S. patent application Ser. No. 08/779,323 has disclosed a hair dryer assembly to lower down the high temperature in the motor. Because a high rotational speed of the motor is the essential factor to create the high temperature, the U.S. patent application provides a structure to bring the outside air current into the motor and remove the heat therein so that the purpose of heat dissipation can be attained and the temperature can be reduced effectively.

[0008] It is obvious from the foregoing that the preceding prior art tries to solve the problem with regard to the noise, the vibration and the high temperature under a condition of maintaining a high rotational speed of the motor. However, it is not a fundamental solution to the problem, and, actually, key points for solving the problem can be listed in the following:

[0009] 1. A high flow velocity may generate sound, and, especially, a loud sound can form easily during the air current turning a direction. Hence, the arrangement in the prior art can reduce very limited decibels for the noise.

[0010] 2. A large noise can be emitted in case of the air current moving a longer distance under a high flow velocity.

[0011] 3. The blade wheel in the hair dryer usually propels the air in a way of the blades thereof flapping the air along a vertical direction or an approximate vertical direction and this is a factor to produce the noise and the vibration too.

[0012] 4. It merely can solve the problem with regard to the noise, the vibration, and the high temperature resulting from the high rotational speed of the motor partially because the high rotational speed is kept unchanged.

[0013] 5. The higher the rotational speed of the motor, the more electricity is consumed and the stronger electromagnetic wave creates. It is known that a stronger electromagnetic wave is harmful to the human body intangibly.

[0014] In order to overcome the preceding drawbacks, it is necessary for a hair dryer to have the following improvements:

[0015] 1. A revised structure of the blade wheel has to be performed.

[0016] 2. The moving distance of the air current with a high flow velocity in the hair dryer has to be shortened.

[0017] 3. The motor has to have a low rotational speed instead of a high rotational speed.

[0018] Thus, problems such as the noise, the vibration, the high temperature of the motor, and the electromagnetic wave can be solved effectively and the harm affected by the drawbacks can be lowered down to the least. But, the motor with a low rotational speed usually leads to a low flow velocity and a low flow rate so that no technique can breakthrough the bottleneck till now.

SUMMARY OF THE INVENTION

[0019] The present invention adopts a principle for accelerating the air gradually such that multiple stages of fan blade assemblies are utilized and driven by a low speed motor to accelerate the moving air current stage by stage gradually and the air current can be sent out from the hair dryer with a powerful velocity and the air current feed device does not generate the noise. In the meantime, the present invention has applied the Bernoulli's Law and the Venturi to increase the flow velocity of air and the flow rate. In addition, the conventional centrifugal type hair dryer and the conventional axial flow type hair dryer can be improved by way of the Bernoulli's Law and the Venturi to accelerate the air current in the hair dryer and lower down the noise, the vibration, the electromagnetic wave, and the temperature with a low speed of the motor. The present invention provides a most important feature that the air current has a highest flow velocity at the heat wire, which is located at the head end of the hair dryer, and the noise merely occurs at the same area instead of occurring from air inlet as the conventional one does.

[0020] Accordingly, a primary object of the present invention is to provide a hair dryer, which can eliminate the noise generated from an air current feed device during the air current entering a casing thereof.

[0021] Another object of the present invention is to provide a hair dryer, which can lower down the temperature of a motor therein and reduce the electromagnetic wave thereof effectively.

[0022] A further object of the present invention is to provide a hair dryer, which can reduce the vibration derived from the motor and the blade wheel because of high rotational speed.

[0023] A further object of the present invention is to provide a hair dryer, in which the air current has a high velocity at an area of the heat wire to eliminate or greatly reduce the noise.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention can be more fully understood by reference to the following description and accompanying drawings, in which:

[0025]FIG. 1 is a sectional view of a conventional centrifugal type hair dryer;

[0026]FIG. 2 is a sectional view of a conventional axial flow type hair dryer;

[0027]FIG. 3 is a sectional view of a hair dryer according to the present invention in a first preferred embodiment thereof;

[0028]FIG. 4 is a sectional view illustrating an arrangement for accelerating the air current in the hair dryer shown in FIG. 3;

[0029]FIG. 5 is a sectional view of a hair dryer according to the present invention in a second preferred embodiment thereof;

[0030]FIG. 6 is a sectional view illustrating an arrangement for accelerating the air current in the hair dryer shown in FIG. 5;

[0031]FIG. 7 is a fragmentary sectional view of the hair dryer of the first or the second embodiment at the casing thereof providing an auxiliary device for accelerating the air current additionally;

[0032]FIG. 8 is a fragmentary sectional view of a centrifugal type hair dryer at the casing thereof providing an auxiliary arrangement for accelerating the air current additionally; and

[0033]FIG. 9 is a fragmentary sectional view of an axial flow type hair dryer at the casing thereof providing an auxiliary arrangement for accelerating the air current additionally.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Referring to FIG. 3, a hair dryer according to the present invention in the first preferred embodiment thereof provides a casing 20 with inner ribs 21 and a low speed motor 22 is mounted at a hollow central space surrounded by the inner ribs 21. The motor 22 can be fixed in place firmly by way of the inner ribs 21 in addition to the original fixing parts thereof, which are not shown in FIG. 3, to reduce the vibration generated from the motor 22 during running. A central shaft of the motor 22 at an end thereof is attached with a first fan blade assembly 23 and the first fan blade assembly is disposed near the rear end of the casing 20, and at the other end thereof is attached with a second and third fan blade assemblies 24, 25 such that it can form a multi-stage air feed device 26. As soon as the motor 22 is powered on, the three fan blade assemblies 23, 24, 25 can rotate simultaneously, and because the respective fan blade assembly has been designed to propel the air without occurring turbulence so that the noise results from the fan blade assemblies thereof during beating the air. The first fan blade assembly 23 can suck the outside air into the casing 20 through the inlet at the rear end of the casing 20 and pushes the air toward the second and the third fan blade assemblies 24, 25, and the second and the third fan assemblies further propel the moving air current forward to perform a function of further acceleration. Thus, the air current can flow in a state of high velocity through a heat wire (not shown) in the head part of the casing 20. In order to obtain a high flow velocity of the air current, the second and the third fan blade assemblies 24, 25 can be provided with a capacity higher than that of the first fan assembly 23 respectively to produce a negative pressure between the first fan blade assembly and the second and the third fan blade assemblies 24, 25 so that a sate of vacuum can be formed in the hair dryer and the atmosphere can force the outside air into the casing 20 speedily. Hence, a strong air current with high flow velocity is possible to be sent out from the casing 20. The advantages of the hair dryer illustrated in the first embodiment can be summarized in the following:

[0035] 1. The air current feed device will not leave out part of the air current at outside so as not to form a turbulence with noise as the blade wheel in the conventional hair dryer does.

[0036] 2. The air current feed device can speed up the air current gradually so that it is not possible for the air current to generate excessive noise during passing through the air current feed device.

[0037] 4. The motor provides a lower rotational speed so that the noise, the vibration, and the high magnetic wave can not be produced in the hair dryer.

[0038] Referring to FIG. 4, an additional arrangement for accelerating the velocity of the air current in the hair dryer shown in FIG. 3 is illustrated. A turbulent part 27 is disposed in front of the third fan blade assembly 25 and the turbulent part 27 is supported with holding ribs 28 in the casing 20. Due to the turbulent part 27, the inner diameter of the casing 20 is reduced such that the discharged air current can be accelerated and reinforced. In addition, the holding ribs 28 can be provided with a shape of spiral or an inclined angle such that the air current can have a rotational movement so as to obtain a better effect of acceleration.

[0039] Besides, a muffle mask 30 can be adapted to an outlet at the head part of the casing 20 to eliminate the noise resulting from an excessive flow velocity. The muffle mask 30 has an inner mask 31 with a plurality of sound removing apertures 32, and a ventilation opening 33 is disposed at a central position thereof to eliminate the noise generated by the hair dryer. It is clear that the hair dryer of the present invention in the first embodiment thereof can eliminate the noise by way of the low rotational speed of the air current feed device and the muffle mask 30 can enhance the removal of noise resulting from the hair dryer. The muffle mask 30 can be mounted to a conventional hair dryer too to perform a function of noise reduction.

[0040] Referring to FIG. 5, a second preferred embodiment of the hair dryer according to the present invention is illustrated. An air current feed device 49 provides a drive transmission different from the first embodiment of the present invention. A chamber 41 is provided in the casing 40 and a motor 47 is fixedly attached to the casing in the chamber 41. The chamber 41 at two opposite lateral sides thereof has a support frame 42 respectively with two ends thereof being fixed to the casing 40, and an axial shaft 43 is fixedly arranged between the two support frames 42 with a bearing 44 being attached to both ends of the shaft 43 respectively. Further, a first fan blade assembly 45 and a second fan blade assembly 46 are arranged to fit with one of the bearings 44 respectively, and the first and the second fan assemblies 45, 46 are driven by the motor 47 via transmission parts 48 such as pulleys with a belt, or a gear train. Hence, an air current feed device 49, which comprises the shaft 43, the bearings 44, the fan assemblies 45, 45, the motor 47, and the transmission parts 48, can be formed in the chamber 41. As shown in FIG. 5, pulleys with a belt are utilized as the transmission parts 48, and it can be seen that the pulley attached to the right end of the motor shaft provides a diameter thereof greater than that of the pulley attached to the left end of the motor shaft. Thus, the second fan blade assembly 46 has a higher rotational speed than the first fan blade assembly 45 such that a speed difference resulting from different pulley sizes leads to the air sucked into the casing 40 by the fan blade assemblies 45, 46 can be accelerated gradually so as to obtain an effect of reinforcing the air current during the hair dryer in a state of running. In the meantime, a negative pressure may be formed because of the faster speed of the second fan blade assembly 46 so that the air outside the casing 40 can flow into the casing 40 with a faster speed and a high flow rate of the discharged air current can be obtained substantially. Moreover, the second fan blade assembly 46 can be made with a size thereof greater the first fan blade assembly 45 to increase the negative pressure between the fan assemblies 45, 46 such that a much greater flow rate of the discharged air current can be obtained.

[0041] Referring to FIG. 6, a further arrangement for accelerating the velocity of the air current additionally in the hair dryer shown in FIG. 5 is illustrated. A turbulent part 50 is fixedly attached to the shaft 43 or a turbulent part 27 is disposed in front of the air current feed device 49. Similar to the arrangement sown in FIG. 4, the turbulent part 27 is fixedly attached to the casing by way of a holding rib 28. As soon as the air current passes through the turbulent part 50 or the turbulent part 27, a further acceleration can be effected to the air current. Furthermore, a muffle mask 30 can be adapted to the head end of the hair dryer to lower down the decibel value of the noise.

[0042] Referring to FIG. 7, a further embodiment illustrates a casing 50 of the hair dryer can be arranged to provide at least a throat tube part 52 corresponding to the number of the fan blade assemblies and an entrance 53 is disposed at the end of the throat tube part 52. When the air current flows speedily in the casing toward the outlet of the casing 50, the pressure in the casing is less than the atmosphere so that it is in a state of partly vacuum and the air in the throat tube part 52 is sucked to move toward the outlet of casing 50 simultaneously. According to the theory of fluid mechanics, (the cross section area of the air current)×(the flow velocity of the air current)=a constant value, the air current in the throat tube part 52 has a much smaller cross section with a much higher flow velocity so that a greater amount of air can enter the casing through the throat tube part 52 and a greater amount of discharged air current with a higher discharged velocity.

[0043] Referring to FIGS. 8 and 9, the turbulent part and the throat tube part in the preceding description also can be applied to the prior art shown in FIGS. 1 and 2. As shown in FIGS. 8 and 9, a casing 60 of a centrifugal type hair dryer and a casing 70 of an axial flow type hair dryer provide throat tube parts 61, 71 with entrances 62, 72 respectively, and a turbulent part 64, 74 is disposed between the blade wheel 65, 75 and the throat tube parts 61, 71 respectively. The turbulent part 64,74 is fixedly attached to the casing 60, 70 by way of the support rib 63, 73. When the blade wheel 65, 75 is driven to rotate, the air current can pass over the turbulent part 64, 74, at which a smaller passage for the air current is offered, so that an accelerated speed can be attained. Meanwhile, the air current in the throat tube part 61, 71 is sucked into the casing in a state of vacuum and the outside air with atmosphere can move into the casing 60, 70 through the throat tube part 61, 71 fast because of the acceleration caused by the negative pressure. Thus, a supposed flow velocity with a required flow rate can be maintained and the noise also can be lower down effectively.

[0044] It is appreciated from the foregoing, the present invention can offer a motor with low rotational speed to reduce the noise source resulting from the motor and the fan, and the flow velocity of the air current can be accelerated by way of a reduced cross section, a negative pressure, and an arrangement of multiple fan blade assemblies respectively. Hence, the noise can merely occur at positions around the heat wire and the head part of the casing. In addition, the muffle mask can be adapted to the head part of the casing to eliminate the noise generating from the high air current at the outlet. Therefore, the present invention secures the effect of noise cancellation substantially. Besides, the low rotational speed of the motor also can reduce the electromagnetic wave and the temperature, which may be produced by the motor during running.

[0045] While the invention has been described with reference to the preferred embodiments, it is to be understood that modifications or variations may be easily made without departing from the spirit of the invention, which is defined by the appended claims. 

What is claimed is:
 1. A hair dryer, comprising: a casing with a front end a rear end; and an air current feed device, being disposed in the casing next to the rear end thereof, and further comprising a motor, being fixedly attached to the casing; a plurality of fan blade assemblies, being arranged coaxially, and being driven by the motor.
 2. The hair dryer according to claim 1, wherein the motor has a central shaft extending axially toward the front end and rear end of the motor respectively and the fan blade assemblies are fixed the rotational shaft respectively.
 3. The hair dryer according to claim 1, wherein first one of the fan blade assemblies is nearest the front end of the casing and a turbulent part is located between the first fan blade assembly and the front end of the casing.
 4. The hair dryer according to claim 1, wherein the air current feed device further comprises an axial shaft for being attached with the fan blade assemblies and the axial shaft is driven by the motor via a plurality of transmission parts.
 5. The hair dryer according to claim 4, wherein a further turbulent part is fixed to the axial shaft between a second and a third ones of the fan blade assemblies.
 6. The hair dryer according to claim 1, wherein the casing is provided with at least a throat tube part corresponding to the fan blade assemblies.
 7. A hair dryer, comprising: a casing with a front end; and a blade wheel, being disposed in the casing; characterized in that a lateral side of the blade wheel provides a turbulent part fixedly attached to the casing.
 8. The hair dryer according to claim 7, wherein the casing is provided with at least a throat tube part behind the turbulent part.
 9. The hair dryer according to according to claim 1, wherein the head end of the casing fits with a muffle mask.
 10. The hair dryer according to according to claim 7, wherein the front end of the casing fits with a muffle mask. 